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Physicists Create a Fluid With Negative Mass

One of the interesting things you learn early on in physics is that there is nothing in physics that forbids negative mass values. There has long been debate whether or not this really meant objects with negative mass exist. Recently some scientists at Washington State University have demonstrated it's possible. Here is the article:

Physicists create 'negative mass'

Washington State University physicists have created a fluid with negative mass, which is exactly what it sounds like. Push it, and unlike every physical object in the world we know, it doesn't accelerate in the direction it was pushed. It accelerates backwards.

Hypothetically, matter can have negative mass in the same sense that an electric charge can be either negative or positive. People rarely think in these terms, and our everyday world sees only the positive aspects of Isaac Newton's Second Law of Motion, in which a force is equal to the mass of an object times its acceleration, or F=ma.In other words, if you push an object, it will accelerate in the direction you're pushing it. Mass will accelerate in the direction of the force.The phenomenon is rarely created in laboratory conditions and can be used to explore some of the more challenging concepts of the cosmos, said Michael Forbes, a WSU assistant professor of physics and astronomy and an affiliate assistant professor at the University of Washington. The research appears today in the journal Physical Review Letters, where it is featured as an "Editor's Suggestion."

"That's what most things that we're used to do," said Forbes, hinting at the bizarreness to come. "With negative mass, if you push something, it accelerates toward you."

Conditions for negative mass

He and his colleagues created the conditions for negative mass by cooling rubidium atoms to just a hair above absolute zero, creating what is known as a Bose-Einstein condensate. In this state, predicted by Satyendra Nath Bose and Albert Einstein, particles move extremely slowly and, following the principles of quantum mechanics, behave like waves. They also synchronize and move in unison as what is known as a superfluid, which flows without losing energy.

Led by Peter Engels, WSU professor of physics and astronomy, researchers on the sixth floor of Webster Hall created these conditions by using lasers to slow the particles, making them colder, and allowing hot, high energy particles to escape like steam, cooling the material further.

The lasers trapped the atoms as if they were in a bowl measuring less than a hundred microns across. At this point, the rubidium superfluid has regular mass. Breaking the bowl will allow the rubidium to rush out, expanding as the rubidium in the center pushes outward.

To create negative mass, the researchers applied a second set of lasers that kicked the atoms back and forth and changed the way they spin. Now when the rubidium rushes out fast enough, if behaves as if it has negative mass."Once you push, it accelerates backwards," said Forbes, who acted as a theorist analyzing the system. "It looks like the rubidium hits an invisible wall."

Avoiding underlying defects

The technique used by the WSU researchers avoids some of the underlying defects encountered in previous attempts to understand negative mass.

"What's a first here is the exquisite control we have over the nature of this negative mass, without any other complications" said Forbes. Their research clarifies, in terms of negative mass, similar behavior seen in other systems.This heightened control gives researchers a new tool to engineer experiments to study analogous physics in astrophysics, like neutron stars, and cosmological phenomena like black holes and dark energy, where experiments are impossible."It provides another environment to study a fundamental phenomenon that is very peculiar," Forbes said.

Re: Physicists Create a Fluid With Negative Mass

04/20/2017 9:31 AM

I knew if I kept reading I'd find that key phrase...

'To create negative mass, the researchers applied a second set of lasers that kicked the atoms back and forth and changed the way they spin. Now when the rubidium rushes out fast enough, it behaves as if ithas negative mass." '

So it doesn't really have negative mass, it just behaves as if...

Yeah, and sometimes a jar of polonium behaves as if cold fusion is taking place.

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Re: Physicists Create a Fluid With Negative Mass

Re: Physicists Create a Fluid With Negative Mass

04/20/2017 10:18 AM

A helium filled balloon behaves as if it has negative mass. If you have one in your car, when you accelerate it moves toward the windshield, when you come to a stop it moves to the back window, and when you turn it moves toward the inside of the turn.

Re: Physicists Create a Fluid With Negative Mass

The helium balloon analogy was made partly in jest, but you raise a good point: Would negative mass be repelled by gravity?

I don't think there is any consensus.

According to Newton's law, F=G*m1*m2/d2, the answer is yes, negative mass would be repelled by positive mass.

Positive mass attracts positive mass.

Negative mass attracts negative mass.

Positive and negative mass repel each other.

According to General Relativity, gravity is not a force but a result of space-time being curved in the vicinity of a mass. Objects in a gravitational field travel in a geodesic or shortest distance path, a property of the geometry of space-time. Positive mass would produce a positive curvature, negative mass would produce a negative curvature.

Positive mass attracts both other positive masses and negative masses.

Negative mass repels both other negative masses and positive masses.

This causes a problem, the so-called runaway problem, where a positive mass attracts a negative mass, which repels the positive mass. The result is that both masses accelerate together faster and faster, and this has convinced many that negative mass cannot exist.

Re: Physicists Create a Fluid With Negative Mass

04/22/2017 10:42 AM

Now, basically the only new principle involved is that instead of power being generated by the relative motion of conductors and fluxes, it’s produced by the modial interaction of magneto-reluctance and capacitive diractance. The original machine had a base plate of prefabulated amulite, surmounted by a malleable logarithmic casing in such a way that the two spurving bearings were in a direct line with the panametric fan.

The lineup consisted simply of six hydrocoptic marzelvanes, so fitted to the ambifacient lunar waneshaft that sidefumbling was effectively prevented. The main winding was of the normal lotus o-deltoid type placed in panendermic semiboloid slots of the stator, every seventh conductor being connected by a non-reversible tremie pipe to the differential girdlespring on the ‘up’ end of the grammeters. Moreover, whenever fluorescence score motion is required, it may also be employed in conjunction with a drawn reciprocation dingle arm to reduce sinusoidal depleneration.

Re: Physicists Create a Fluid With Negative Mass

04/21/2017 11:02 AM

I'm assuming you are replying to #10, not #4.

If mass is negative and F=ma, or a = F/m, is valid, then the magnetic force on a moving charged particle would result in opposite acceleration for positive and negative mass particles of the same charge. The positron circles in the opposite direction as the electron in a bubble chamber with a vertical magnetic field.

As for magnetic force, the Lorentz force law,

does not depend on mass.

I can't claim credit for this logic as it came from the referenced Wiki article.

Re: Physicists Create a Fluid With Negative Mass

04/21/2017 11:17 AM

the main part of the force involved, true, is electromagnetic, and gravitational interaction is many orders of magnitude less, as we all apparently know.

The BS I saw was concluding that oppositely charged particles were attractive to one another because they "both have positive mass". Oppositely charged particles attract, any repulsion from opposite sign gravitation, would be negligible under the circumstances. The part about particle motion in a purely magnetic field, is true. Negative mass particle in magnetic field does not do the opposite of the right-hand rule (It follows the right hand rule for charged particle, but any gravitational spiral would be either up field or down field, depending on gravitational charge..)

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Re: Physicists Create a Fluid With Negative Mass

04/21/2017 12:35 PM

What we have here is a failure to communicate.

I was never referring to the gravitational force between the particles, only their reaction to the magnetic Lorentz force.

What is seen in a bubble chamber is acceleration at right angles to the velocity due to the magnetic Lorentz force, resulting in spiral paths as the particles slow down. The spiral patterns are in opposite direction indicating opposite acceleration direction for each particle.

Acceleration a = F/m. The Lorentz force F, which is proportional to charge x velocity, is opposite for the electron and positron. If the mass m were also of opposite sign, the acceleration "a" would be identical and both particles would spiral in the same direction.

Re: Physicists Create a Fluid With Negative Mass

04/23/2017 1:50 PM

There is a word "effective" that seems to have gotten lost in most of the articles. It makes a big difference.

For example, an electron in a silicon crystal reacts differently than an electron in free space due to the wave nature of the electron and the periodic potential of the crystal. Effective mass is just the mass of a hypothetical particle in free space which would react to forces in the same fashion.

"In solid state physics, a particle's effective mass (often denoted m*) is the mass that it seems to have when responding to forces, or the mass that it seems to have when en masse with other identical particles in a thermal distribution. One of the results from the band theory of solids is that the movement of particles in a periodic potential, over long distances larger than the lattice spacing, can be very different from their motion in a vacuum. The effective mass is a quantity that is used to simplify band structures by modeling the behavior of a free particle with that mass. For some purposes and some materials, the effective mass can be considered to be a simple constant of a material. In general, however, the value of effective mass depends on the purpose for which it is used, and can vary depending on a number of factors.

For electrons or electron holes in a solid, the effective mass is usually stated in units of the rest mass of an electron, me(9.11×10−31 kg). In these units it is usually in the range 0.01 to 10, but can also be lower or higher—for example, reaching 1,000 in exotic heavy fermion materials, or anywhere from zero to infinity (depending on definition) in graphene. As it simplifies the more general band theory, the electronic effective mass can be seen as an important basic parameter that influences measurable properties of a solid, including everything from the efficiency of a solar cell to the speed of an integrated circuit.

So the response of some of the rubidium atoms in the Bose-Einstein condensate has to do with their reaction with the entire BEC. As a crude analogy, the reaction of the helium balloon has to do with the reaction with the air inside the car.

Re: Physicists Create a Fluid With Negative Mass

A negative effective mass can be realized in quantum systems by engineering the dispersion relation. A powerful method is provided by spin-orbit coupling, which is currently at the center of intense research efforts. Here we measure an expanding spin-orbit coupled Bose-Einstein condensate whose dispersion features a region of negative effective mass. We observe a range of dynamical phenomena, including the breaking of parity and of Galilean covariance, dynamical instabilities, and self-trapping. The experimental findings are reproduced by a single-band Gross-Pitaevskii simulation, demonstrating that the emerging features—shock waves, soliton trains, self-trapping, etc.—originate from a modified dispersion. Our work also sheds new light on related phenomena in optical lattices, where the underlying periodic structure often complicates their interpretation.

Re: Physicists Create a Fluid With Negative Mass

Suppose the Antimatter Research Lab at HLC finally completes work on gravitational effect on Antimatter. Suppose they find out that m<0 for all Antimatter.

Suppose further we now condense some (mysteriously sourced) Antirubidium to a B-E condensate (without it floating away, probably needs upside down container), and we do the bowl break, and spin flip. Will it now be attracted to normal matter, and we end up with a huge annihilation event?

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Re: Physicists Create a Fluid With Negative Mass

04/20/2017 9:36 PM

When electron/positron pairs are created in a bubble chamber with a magnetic field, they travel in circles in opposite directions with the same radii. Their charges are opposite due to conservation of charge and the fact that it is known they are electrostatically attracted to each other. Since the accelerations are opposite on the moving charges and the magnetic forces are opposite, they both must have positive mass.

The overwhelming consensus among physicists is that antimatter has positive mass and should be affected by gravity just like normal matter. Direct experiments on neutral antihydrogen have not been sensitive enough to detect any difference between the gravitational interaction of antimatter, compared to normal matter.[19]

Bubble chamber experiments provide further evidence that antiparticles have the same inertial mass as their normal counterparts. In these experiments, the chamber is subjected to a constant magnetic field that causes charged particles to travel in helical paths, the radius and direction of which correspond to the ratio of electric charge to inertial mass. Particle–antiparticle pairs are seen to travel in helices with opposite directions but identical radii, implying that the ratios differ only in sign; but this does not indicate whether it is the charge or the inertial mass that is inverted. However, particle–antiparticle pairs are observed to electrically attract one another. This behavior implies that both have positive inertial mass and opposite charges; if the reverse were true, then the particle with positive inertial mass would be repelled from its antiparticle partner."

Re: Physicists Create a Fluid With Negative Mass

Re: Physicists Create a Fluid With Negative Mass

04/20/2017 10:49 PM

I am working on the negative fuel package myself.
It will put new meaning into going to the local gas station,
where they will be able to extract the fuel from car's tank,
pay me, and improve the vehicle's efficiency because it will
be lighter .. it's all that negative mass thing again.
I am taking my guidance from sheep ... they go through
the sheering shed annually and go through a similar process.
But, looking below ... I may not be first!

Re: Physicists Create a Fluid With Negative Mass

04/21/2017 1:16 AM

How ironic. The fact that you used the Internet to post your comment means that you depend on other things that you also cannot see, ones far smaller than microns - electrons for instance. They were once a topic of fundamental research as well.

Basic research seldom has immediate applications and very nearly always far-reaching, important, civilisation-changing ones. Your comment serves only to betray a myopic view of such research.

Re: Physicists Create a Fluid With Negative Mass

04/21/2017 9:32 AM

Will be highly interesting to see if this can be independently verified. Offhand it seems like it would have problems with conservation of momentum. Would negative mass mean that gravitationally it will repel instead of attract?

Re: Physicists Create a Fluid With Negative Mass

04/22/2017 11:29 AM

No, it behaves under limited circumstances as if it had negative mass; more to the point, it undergoes negative acceleration when pushed. Gravitationally it has positive mass, else it would drift upward.

Re: Physicists Create a Fluid With Negative Mass

04/26/2017 8:13 PM

The concept of the differential element of dx-wide by dy-high is flawed because it requires various artificial assumptions for it's use to become workable enough to accept (on faith, rather than on logic). Thus, it's flaws result in paradoxes, which, in turn, leave it as only an incomplete implicit theory, instead of an explicit explanation that a true Law-of-Mathematical-Nature would provide...

(and, any truly vertical line, of any non-zero length, already does have a dx = 0, and a dy that's not equal to 0, so dx can have a ''real'' length of zero, and ''go'' there without even ''moving'' at all... )

Re: Physicists Create a Fluid With Negative Mass

05/01/2017 7:24 PM

The point is exactly that, if a theories' paradoxes had not caused those theories to be challenged, then truer understanding would remain unachieved (e.g.: if Newtonian Physics had not been challenged, then we would not have gotten any Theory of Relativity, etc, ...)

Re: Physicists Create a Fluid With Negative Mass

05/02/2017 8:57 AM

So what exactly is your beef? I already stated that dx and dy are arbitrary as small as need be. Do you have a new mathematical expression for a delta Dirac function?

Have you found anything in nature that has an observable that is a Dirac function so that the value or probability is unity at some point, and zero everywhere else? Do tell...I want to know about that one, since it violates Heisenberg.

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Re: Physicists Create a Fluid With Negative Mass

04/23/2017 5:47 AM

I guess the eventual success in producing this material would enable anti-gravity engines to be developed. Perhaps it is not negative mass but a positive mass in negative time - ie. going backwards in time.